Movable contact member for electric switches



Dec. 15, 1931. T. E. KEARNS MOVABLE CONTACT MEMBER FOR ELECTRIC SWITCHES Filed Oct. 29, 1930 i 1 a Q r In vent 01" 7770277525 E K 551 175 fl z u ngy Patented Dec. 15, 1931 UNITED STATES PATENT OFFICE THOMAS E. KEARNS, OF MARTFORD, CONNECTICUT ASSIQNOB TO COLTS PATENT FIRE ARMS MANUFACTURING 00., OF HARTFORD, CONNECTICUT, A CORPORATION OF comcrrcur MOVABLE CONTACT MEMBER FOR ELECTRIC SWITCHES Application filed October 29 1930. Serial No. 492,061.

The present invention relates particularly to electric circuit controlling appliances of the type disclosed in the patents to Joseph Sachs, No. 1,754,443 and No. 1,754,445 dated April 15, 1930 and No. 1,755,367 dated April 22, 1930.

The principal object of the invention is to provide for a circuit controlling appliance or switch of the type specified, an improved movable switching member or slide which is adapted to be economically manufactured and which has other important advantages.

In the accompanying drawings I have illustrated my invention in conjunction with a switch such as shown in the before-mentioned Patent No. 1,754,445, but it will be understood that this particular switch construction has been selected merely for purposes of illustration and that the invention is by no means limited to this particular switch construction. In general, the drawings are not to be construed as defining or limiting the invention, the claims forming a part of this specification being relied upon for. this purpose.

Of the drawings:

Fig. 1 is a front view of a switch appliance embodying the invention, and showing the movable -switch contact members in closedcircuit positions.

Fig. 2 is a vertical sectional view taken along the line 2-2 of Fig. 1, but showing the movable switch contact members in opencircuit positions.

Fig. 3 is a view showing the several parts of one of the movable switch contact members separated from each other so that the construction ofthe said parts and their relationship may be more readily apparent.

Fig. 4 is a transverse sectional view through the movable switch contact member taken along the lines 44 of Figs. 1 and 2.

Fig. 5 is a transverse sectional view through the movable switch contact member taken along the line 55 of Fig. 1.

An appliance embodying the invention may be combined with a fuse block and the appliance as a whole maybe enclosed in a suitable box or cabinet. Such an enclosed fused switch is shown in the drawings and will be described. Referring to the drawings it will be observed that the parts of the fused switch unit of the appliance are symmetrically disposed with respect to the vertical central plane of the said unit. For the sake of convenience and simplicity of description. I

will describe in detail only those parts on:

one side of the said plane, it being underalso includes a second insulating means which serves as a supporting device and is secured directly to the said supporting wall. This insulating means may comprise two separate members 2, 2 secured to the back of the cabinet by suitable means such as screws 3', 3. The

several conducting parts of the fused switch unit are connected with the insulating members 1 and 2, 2.

The fuse contacts are represented at 3 and 4, these being carried directly by the base 1. There are shown contacts for receiving a fuse F of the cartridge enclosed type, but the in vention is not so limited. Located in normally fixed relation to the fuse contacts and preferably at least in part in the space behind the plane of the rear face of the base 1 is at least one and preferably two switch devices, each of which comprises two opposed stationary switch contacts and a movable switching means which includes a contact adapted to engage or disengage both of the stationary contacts to make or break the electrical connections between them.

The opposed stationary contacts for one switch device are represented at 5. and 6 and the opposed stationary switch contacts for the other switch device are indicated at 7' and 8. The several stationary switch contacts are mounted on supporting elements 9, 10, 11 and 12 which project forward from the supporting devices 2, 2 and which may besecured thereto by screws 13,13. Each of the switch contacts proper may be of a general U-shape 2 memos and is provided with a laterally extending flange engaging the corresponding supporting element and connected thereto.

The supporting elements 9 and 11 are extended upward and downward respectively to positions directly back of the. fuse contacts 3 switch contact, and when there aretwo pairs 20 of stationary switch contacts as here shown there are two movable contacts as indicated at 18 and 19. For carrying the movable contact or the movable contacts there is provided a flat insulating element 20 to which the present invention particularly relates. I movable switch contact or contacts and the carrying insulating element therefor constitute what will be called a movable contact member. The movable contact member is preferably guided at the front by the base 1 andat the rear by the supporting device 2, 2. It will be understood that when the contact member is moved to its lower position as shown in Fig. 1 the two contacts 18 and 19 are simultaneously engaged with the respective pairs of switch contacts 5, 6 and 7, 8 to complete the electrical connection through the switching devices. It will be further understood that when the switch contact member is moved to its upper position as shown in Fig. 2 the two contacts 18 and 19 are simultaneously disengaged from the switch contacts The fused switch device is preferably mounted in a suitable casing or cabinet such as the cabinet 21 shown in the drawings. The cabinet-21 is shown as being provided with a front cover 22 which is openable so as to permit access to the enclosed switch and fuse parts. For operating the switch contact members, there is provided a spindle 23 which extends through bearing apertures in the side walls of the cabinet 21 and which is provided with an operating handle 24 on the exterior of the. cabinet. Within the cabinet the operating spindle 23 is provided with a cranked portlon which extends through slots 25 formed in the insulating elements 20 of the movable switch contact members. The operating spindle 23 serves as a means for moving both of the switch contact members so as to make and break the respective circuit 7 connections substantially simultaneously as already described.

In accordance with the present invention The.

the fiat insulating element 20 instead of being formed of a single piece of insulating material is formed of two separate similar plates 20 and 20" which are shown separately in Fig. 3 and which are shown in their normal face to face relationship in Fig. 1. The two plates are provided with similar slots 25 and 25 which normally register with each other to form the before-mentioned composite slot 25 for the operating element. In conjunction with at least one of the movable contacts, as for instance thecontact 18, the two plates are provided respectively with slots 18 and 18". As shown the slot 18 extends upward from the bottom edge of the plate 20? and the slot 18 extends downward from the top edge of the plate 20 The two slots are so positioned that their inner end portions are normally in register with each other. When the slots are thus in register they provide an opening which extends transversely entirely through the composite element 20. and which is closed at the top and at the bottom. The closure at the top is provided by the top wall of the slot 181and the closure at the bottom is provided by the bottom wall of the slot 18".

As concerns the structural details of the contacts 18 and 19 I do not limit myself but I have shown contacts similar to those shown in the before-mentioned Sachs patents. Each contact 18 or 19 comprises a U-shaped strip of metal having the legs of the U substantially parallel to and located'closely adjacent the outer walls of the insulating element 20 and having the connecting or bridge portions of the U extending through the be? fore-mentioned opening formed by the slots 18 and 18".

The novel relationship between the contact element 18 and the insulating platesQO and 20 will be more readily apparent from a studyof Fig. 3- This shows the lower part of the contact 18 entered in the slot 18 and shows the upper partof the contact 18 entered in the slot 18. It will be evident that when the plate .20 is moved vertically downward from the position shown the two plates 20 and 20 will come into registeringface to face relationship with the contact 18 in engagement with the bottom wall of the slot 18 and with the top wall of the slot 18.

The two plates 20' and 20 are preferably mechanically connected by means additional to the movable contact or contacts. For this purpose I have shown rivets 26 and 27 which extend respectively through holes 26, 26 and 27 27' in the said plates 20 and 20". These rivets are preferably formed of insulating material and one of them, that is, the rivet 26 is located at that side of the two slots 18* and 18 which is opposite the slot 25' through which the operating spindle extends. t will be apparent that considered separately each of the plates 20 and 20 is considerably weakened by the slot 18 or l8 formed therein. If the lower portions of the plates were not mechanically connected there would be a tendency for the plates to break at the reduced portions adjacent the ends of the slots. However, when the lower portions of the plates are connected by means such as the rivet 26 each plate reinforces the other and the sections of reduced cross sectional area are subject only to simple tension stresses.

Preferably the insulating rivets 26 and 2 7 are utilized, not only for mechanically connecting the two plates 20 and 20 as already described, but also for providing frictional resistance tending to hold the movable switch member in its upper open-circuit position as-shown in Fig. 2. The said rivets 26 and 27 are so located that when the switch member is in its upper position as shown the said rivets are positioned between the stationary switch contacts and in frictional engagement therewith. This frictional engagement between the rivets 26 and 27 and the corresponding stationary switch contacts resists downward movement of the switch member and helps to prevent any accidental or unintentional closing of the switch.

The second contact 19 when provided may be connected with the plates 20 and 20 by means of slots similar to the described slots 18 and 18". However to economize space at the upper end of, the movable switch member it may be preferable to attach the contact 19 by other means. As shown the two plates 20 and 20 are formed with notches 19 and 19" of the proper size to receive the connecting or bridge portion of the contact 19. The said contact 19 is held in place in the notches 19 and 19 by means of a metallic clip 28 which extends across the ends of the plates and is held in place by means of transverse pins 29 extending through suitable holes in the plates and through ears 30, 30 formed on the clip 28.

With my improved construction important manufacturing economies are attained, particularly in relatively large switches. According to prior practice the insulating element was a single plate of insulating material having therein a slot closed at both ends. When the switch was large it was impracticable to form the slot by punching, and it had to be formed by an expensive machining operation such as milling. With my improved construction the slots can ordinarily be punched on account of the smaller thickness of each plate; and furthermore even when punching is not possible the slots can be made at low cost by sawing from the edges of the plates.

A further economy results from the fact that the contacts can be completed prior to their assembly with the insulating plates. According to prior practice the contacts had to be initially left in an unfinished partly bent condition so that they could be entered through the slots in 'the plates; and the slots had to be wider than otherwise necessary to permit such entering. After the contacts were in place filler pieces had to be inserted in the slots and then the contacts had to be subjected to an additional bending operation to bring them to the desired final shape. All of this is avoided by my invention, as the contacts can be completed at the outset, and the slots can be made of exactly the proper width to receive the contacts, thus avoiding the necessity for filler pieces. Then the parts can be easily assembled as indicated in Fig. 3.

What I claim is:

1. A movable contact member'for a switch having two opposite spaced stationary electrical contacts, the said contact member being adaptedto move between the said stationary contacts and comprising in combination two similar insulating plates connected together in face to face relationship, the said plates being provided with two transverse slots extending respectively from opposite edges of the respective plates and positioned with their inner end portions in register with each other, and a metallic contact element extending through the opening provided by the registering portions of the two slots and held in place by the walls of the said slots, the said element having contact faces located at opposite sides of the two insulating plates and adapted to be engaged with or disengaged from the stationary switch contacts.

2. A movable contact member as set forth in claim 1, wherein the plates are so formed at one side of the slots as to be adapted for engagement with a member for moving the contact member, and wherein there is an element at the opposite side of the slots for mechanically connecting the two plates together.

3. A movable contact member as set forth in claim 1, wherein the two plates have their opposite edges parallel and adapted to guide the contact member for rectilinear movement.

4. In an electric switch, the combination of 2 faces located at opposite sides of the two insulating plates, and means for moving the two-plates and the contact element to cause the latter to be engaged with or disengaged from the stationary contacts. Y

5. In an electric switch, the combination of two opposite spaced stationary electrical contacts, two similar insulating plates positioned in face to face relationship and movable in unison between the two stationary contacts, the said plates beingprovided with two transverse slots extending respectively from opposite edges of the respective plates and positioned with their inner end portions in registerwith each other, a metallic contact element extending through the opening provided by the registering portions of the two slots and held in place by the wallsof the said slots, the said element having contact faces located at opposite sides of the two insulating plates, means engaging the two plates at one side of the slots for moving the said plates and the contact element to cause thelatter to be engaged with or disengaged from the stationary contacts, and an element positioned at the opposite side of the slots and serving to mechanically connect the two plates.

6. In an electric switch, the combination of two opposite spaced stationary electrical contacts, two similar insulating plates positioned in face to facerelationship and movable in unison between the two stationary contacts, the said plates having parallel guiding edges and being provided with two transverse slots extending respectively from opposite edges of the respective plates and positioned with their inner end portions in register with each other, a metallic contact element extending through the opening provided by the registering portions of the two slots and held in place by the walls of the said slots, the said element having contact faces located at opposite sides of the two insulating plates, means for moving the two plates and the contact element to cause the latterto be engaged with or disengaged from the stationary contacts, and a rivet of insulating material connecting the two insulating plates and having projecting portions at opposite sides of the plates, the said rivet being positioned to move between and engage the two stationary contacts when the said conducting contact element is out of engagement therewith.

In testimony whereof I have hereunto set my hand this 27th day of October, 1930.

THOMAS E. KEARNS.

memes 

